Some actions triggered by a key may be incomplete. For example, when I press Enter, I'd like it to go to the next line AND to indent (that saves me a TAB press, and a lot each day). Do you like to type C-a C-k C-k to erase a line ?

Keychord gives the ability to map pairs of simultaneously pressed keys to commands. So you can define some keyboard shortcuts that do not involve Ctrl or Meta.
(In this package, a "key chord" is two keys pressed simultaneously, or a single key quickly pressed twice (excluding Ctrl, Shift or Meta)).

Be careful, do not map two keys that usely go together, or it will be very inconvenient.

The TypeMatrx keyboard is thin, small, has its keys disposed as a matrix, can switch its layout on a keypress (with no need of OS drivers) and, most of all, it has the Enter and the Backspace keys on the middle, so that you access them with your forefinger of both hands. As a result, you stop moving your right wrist on a «big» distance to the right. This is known to be life saving (and my experience said that I can't work without a TypeMatrix).